Burner



March 6, 1934. R. D. CHEESMAN 1,949,560

BURNER Filed July 25, 1932 2 Sheets-Sheet l March 6, 1934. R. D.cHEEsMAN BURNER Filed July 25, 1932 2 Sheets-Sheet 2 arcta @ees m75 9%.@klv Mama/m Patented Mar. 6, 1934 UNITED STATES PATENT OFFICE BURNER'Application July 25, 1932, Serial No. 624,573`

4 Claims.

This invention relates to a method and apparatus for increasing theheating eiciency of burners of the combustion heating type in which aninflammable material, being either a liquid,

I a solid, or a gas, is burned in the presence of a gas, such as oxygencontained in the air, the heat of combustion being transferred byradiation and convection to the body being heated.

Heat transfer from a flame may be by radial tion and convection, theamount of heat transferred by either means varying widely in differentapplications. An accepted law of radiation is that heat transfer byradiation is proportional to the difference of the fourth powers of theab- 152 solute temperatures of the bodies emitting and receiving theradiation. Therefore, as the temperatures increase, radiation becomes amore and more important factor in transferring the heat of the flame tothe body being heated. It has also IDX been demonstrated that theluminosity of a flame determines to a large extent its radiating power.That is to say, a luminous flame transfers far more heat by radiationthan a non-luminous flame at the same temperature, the heat trans- 'zfer from a strictly non-luminous llame being chiefly by convectionalthough all flames carry a certain amount of dustor ash particles,which tend to increase their radiating capacity within narrow limits. Itfollows therefore that by in- ?3'01 creasing the luminosity of a flame amore efficient 40; jdust This dust may consist of such materials asminerals, ores, or carbonaceous matter, but in any event being of suchcomposition as to be heated to incandescence by the flame and therebyimpart luminosity to it. A particular object ofthe invention is toobtain an intimate mixture of ldust with the fuel before burning andpreferably this is accomplished by introducing the dust into the samecurrent of air that delivers the fuel 5.5@ into the combustion chamberso that a thorough .5`5 controlled and the best heating effect obtained,

the invention contemplates the regulation of the amount of dust suppliedto the flame. y

This method may be advantageously carried out in connection withapparatus for calcining or roasting ores or other mineral products under00 conditions where intense heat is required, and a further object ofthe invention is the provision of a burner adapted to utilize the novelmethod stated above. Such a burner for example finds useful applicationin the production of 653 cement clinker in the manufacture ofPortlandcement. In accordance with one embodiment of the invention,means are provided for withdrawing the dust accompanying the productionof the clinker and intimately mixing it with the 70- fuel employed inthe burner, so as to impart increased luminosity to the flame and thusintensify its heating effect. However, the dust if desired may beobtained from a source independent of the material undergoing treatment.Means are 7l`4 provided for regulating the amount of dust admitted tothe flame to obtain the proper luminosity.

The invention Will-be better understood from the following detaildescription of apreferred B0, embodiment ofthe invention taken inconjunction with the annexed drawings in which Figure 1 is a plan viewof an apparatus including a burner and kiln used in the manufacture ofPortland cement; and

Figure 2 is a side elevation of the apparatus of Fig. 1, parts beingbroken away for greater clearness.

In the production of Portland cement by the apparatus shown in Figs. 1and 2, the wet or dry mix of raw materials entering into the compositionof cement, such for example as limestone and clay, or shale or cementrock, 'is fed into the elevated end of an inclined rotary kiln l and asthis kiln slowly revolves the mix is advanced along the bottom of thekiln towards its lower end, constituting a combustion chamber, in whichthere plays a flame 2 which subjects the mix to intense heat. Thecalcined or burned material spills off the end of the kiln as clinkerwhich is subsequently ground up to form Portland cement. The granularclinker issuing from the end of the kiln drops down through a verticalpassageway 3 formed in a hood 4, closing the lower end ofthe inclinedkiln 1, into a clinker pit 5 of oblong shapelocated on a lower floorlevel. The clinker pit is in communication with the elevated end of aninclined rotary cooling cylinder 6 which serves to carry olf the clinkerfrom the pit 5.

For producing within the interior of the kiln the flame 2 which mayextend in some cases to a length of forty feet, there is provided aburner designated generally at A. This burner includes an air-blast pipe7 mounted at one end in a header 8 and having its other end passedthrough the wall of the hood 4 adjacent the open lower end of the kiln.Concentrically arranged within the air-blast pipe and held in positionby means of spoked spacer rings 9 is a burner pipe 10 which extendssubstantially the length of the air-blast pipe 7, but which is ofsomewhat less diameter than the latter so as to afford an air passagebetween the walls of the outer and inner pipes. A pairof exhaust fans l1driven by electric motors 12 acts to discharge air into the header 8 andthence out through air-blast pipe 7 and `.burner pipe 10 into thecombustion chamber of the kiln. The relative proportion of air passingthrough each of the pipes 7 and 10 is regulated by manually-operabledampers 13. For introducing fuel into the current of air passing throughthe burner pipe 10, there is a hopper 14 containing a supply of powderedcoal which is fed along a trough 15 by a screw conveyor 16 anddischarged into a downspout 17 communicating with the burner pipe 10 ata point relatively remote from the discharge end of the burner ypipe.The

speed of the conveyor may be varied by means,

not shown, to control the flame 2.

According to common practice the air supplied by the exhaust fans 11 tothe burner is taken from a locality adjacent the burner or is led infrom outside the establishment and while perhaps having entrainedtherein a small amount of particulate matter, this amount is insufcientto increase the luminosity of the flame to any appreciable degree. Thesame may be said with Y ,respect to the relatively small amount ofashforming impurities contained in the coal and the inconsequentialamount of foreign matter which is usually found intermixed with thecoal. While 5in the past air sometimes has been supplied to L thecombustion chamber of the kiln to promote combustion of the fuel or hasbeen sucked into the combustion chamber by the draft created by theflame, the dust accompanying the air was not recognized as possessingany utility-although probably it served to increase the luminosity ofthe flame to a certain extent. But no attempt was made to utilize thisdust to increase the heating efficiency of the burner by intimatelymixing it with the fuel to impart luminosity to the ame. Nor, so far asI am aware, has it ever co-F ` oblong chamber so as not to be obstructedby the descending stream of clinker is a flue 18 which leads to an airseparator 19 of the whirlwind type and this separator is connected inturn, through a conduit 20, with a compartment 20 located on the intakeside of the fans 11. The fans thus serve to create a draft through thecooling cylinder 6 and through the pit 5 into the fiue 18 as indicatedby the arrows in Fig. 2. The lowerv end of the cooling cylinder, notshown in the figures, is open to afford an unlimited supply of air. Theclinker leaving the kiln l is heated to a high temperature and inpassing through the rotating cooling cylinder 6 there occursconsiderable abrasive and chilling action, resulting in the formation ofa certain amount of dust, and consequently this dust will be drawn inwith the air entering the flue 18. For regulating the amount of dustentering the burner, the air separator 19 is provided with a manualcontrol 21. Practically any type of air separator which is selectivelyadjustable to vary its operating efficiency may be utilized in thisconnection, and as examples of two such types of apparatus reference ismade to U. S. Patent No. 1,393,553 of Leonhardt dated October 11, 1921,and U. S. Patent No. 863,189 of Lauritzen dated August 13, 1907.

ln the form of apparatus just described the dust which accompanies theproduction of clinker may thus be made to serve the useful purpose ofincreasing the efficiency of the burner, besides incidentally conducingto a more healthful condition in the plant by reducing aircontamination. The dust-laden air removed from the cool-l ing cylinder 6and clinker pit 5, is delivered into header 8 from whence it passes outthrough the air-blast pipe 7 and the burner pipe 10. The dust carried bythe air current passing through the burner pipe will be thus mixed withthe particles of powdered coal delivered into this pipe from thedownspout 17, and as the dust and fuel is swept along toward thedischarge end of the burner pipe the dust will become thoroughlydispersed throughout the combustible mixture and will thereby greatlyincrease the luminosity of the ame 2. Since this increase in luminosityas above described improves the heating action of the burner a moreeffective calclnrlg operation will result. The dust borne along by thestreamY of air passing through the air-blast pipe 7 which serves tosupport combustion of the haine will also tend to increase itsluminosity, but since the dust of the air-blast pipe does not enter theflame in intimate association with the fuel, its effect will be lesspronounced.

While the invention is described and illustrated in connection with anapparatus for burning cement, it is to be understood that this is merelyby way of example and that the invention may be utilized in connectionwith other types of apparatus, in which the efcient transfer of heatfrom a ame to a surrounding body is a desideratum.

Nor is the invention limited to use with any particular kind of fuel.When for example oil or gas is employed as fuel, the dust particles maybe introduced into the ame in a manner similar to that which has alreadybeen described in connection with powdered coal.

I claim:

1. An apparatus for producing clinker in the manufacture ofPortland-cement comprising in combination an inclined rotary kiln foradvancing a stream of cement-forming material therealong, and a burnerfor producing a flame within the kiln, said burner having a burner pipeof substantial length for discharging fuel under pressure, cooling meansfor receiving the clinker issuing from the kiln, means forwithdrawing-dust laden air from the cooling means and introducing itinto the burner pipe at a point relatively remote from the discharge endof the burner pipe, and an air separator selectively regulable tocontrol the amount of dust entering the burner pipe.

2. An apparatus for producing clinker. in the manufacture ofPortland-cement comprising in tities of dust from the air entering theburner so combination a rotary kiln arranged to advance a charge ofmaterial therethrough, a burner for producing a ame within the kiln,means for discharging dust-laden air into the burner, and anair-separator adjustable to remove variable quantities of dust from theair discharging into the burner so as to regulate the luminosity of theburner ilame.

3. An apparatus for producing clinker in the manufacture ofPortland-cement comprising in combination a rotary kiln, a burner forproducing a flame within the kiln, a cooler for receiving clinkerissuing from the kiln and subjecting it to agitation to producedust-laden air therein, means for withdrawing the dust-laden air fromthe cooler and introducing it into the burner, and an air-separatoradjustable to remove variable quanas to regulate the luminosity of theburner flame. 4. An apparatus for producing clinker in the manufactureof Portland-cement comprising in combination a rotary kiln arranged toadvance a charge of material therethrough, a burner for producing allame within the kiln, a cooler located adjacent the kiln, means fordirecting material issuing from the kiln into the cooler, said coolerbeing arranged to subject said material to agitation to produce adust-laden air therein, a fan for withdrawing the dust-laden air fromthe cooler and introducing it into the burner and an air-separatoradjustable to remove variable quantities of dust from the air enteringthe burner so as to regulate the luminosity of the burner llame. RICHARDD. CHEESMAN.

